The use of reusable binders is well known. Conventional reusable bindings consist of one-piece binders which have a plurality of fingers that do not interlock or two-piece binding strips that incorporate locking studs and no spine. One-piece bindings generally incorporate a plurality of fingers that are inserted through holes punched along the margin of paper sheets. Using the resilient properties of the binding, the fingers are spread and inserted through the holes in the sheets. The spreading pressure is released and the fingers return to their original position, holding the paper sheets in place. These bindings are typically round in configuration and allow the document to be laid flat along a horizontal surface.
Two-piece binding strips typically require small holes to be punched along the margin of paper sheets. The studs of the male binding strip are inserted through the holes in the sheets. The extending portion of the stud is inserted through a female strip that has locking channels. The extending portion of the stud is manually bent into the locking channel to secure the paper sheets. These bindings have no spine and are difficult to lay flat along a horizontal surface.
Each of these binding systems has its disadvantages. The one-piece bindings require the use of a machine or similar apparatus to hold and spread the binding fingers. The round spine is not aesthetically pleasing and does not resemble traditionally-bound hard cover books or documents. If the binding is filled with an excessive number of paper sheets, the outer sheets can be released from the fingers. In addition, two-piece binding strips do not resemble bound documents. The binding can not be easily laid flat, and the reader is typically required to bend the paper sheets along the inside margin to open the document. Continued opening and closing of the document wears the paper margin such that the original shape of the document is no longer retained.